You won't get any noticeable increase in gaming performance by increasing RAM. Integrated graphics are not good for gaming, you need a dedicated mobile GPU, that's the one upgrade that will considerably improve gaming performance.
I've experimented with quite a few free Antivirus before settling on a paid version. AVG isn't as good as Avira which in turn isn't as good as Avast. Download MalwareBytes as well.
From your laptop, go to run command (Win key+ R)> type 'dxdiag'> press enter> go to display tab> the 'approx total memory' will tell how much VRAM (graphics memory) you have.
Report it to Avast's team, that should solve the issue. Also, check with multiple programs on your side. And you can alternatively put that site in the exceptions list to be able to view them.
Note that I don't own this AV right now so I may be off here.
It has been clearly stated on the Laptop's website page that it has dual graphics:
http://www.samsung.com/nz/consumer/pc-peripherals/notebook-pc/essential/NP355V5C-S07AU
Download SpeedFan, and you can then configure the fan speeds and operation as per your wishes (provided they can auto-adjust, which I'm certain they can).